Titanocene-catalyzed formation of allylsilanes from allyl ethers and chlorosilanes

A new method for silylation of allyl ethers with chlorosilanes has been developed by the use of Cp₂TiCl₂ as a catalyst. This reaction proceeds efficiently at −20 °C in THF using ⁿBuMgCl. A plausible reaction pathway via allyltitanocene intermediate was proposed.     

Reaction of tetrahydropyran with chlorosilanes

Summary In the reaction of tetrahydropyran with chlorosilanes in presence of anhydrous zinc chloride the ring is opened with formation of 1,5-dichloropentane and chlorine-substituted orthosilicic esters. The relative amounts of these products depend on the number of chlorine atoms in the molecule of the chlorosilane with which the tetrahydropyran reacts.     

Some regularities of chlorosilanes etherification

The influence of reagents, solvent polarity, and temperature on the etherification of chlorosilanes ClCH₂SiCl₃, VinSiCl₃, PrSiCl₃, and Ph₃SiCl with ethanol was studied. Influence of reaction temperature on the ratio of the synthesized alkoxysilane and related side-product siloxane is revealed. Use of excess alcohol is shown to increase the content of siloxane. Introduction of FeCl₃ does not affect the synthesis. Solvents are shown to influence the reaction rate: the rate constant increases with increasing ? parameter of the solvent. The rate constant of etherification of chlorosilanes with ethanol falls in the series: ClCH₂SiCl₃ > VinSiCl₃ > PrSiCl₃. An explanation of the regularities is suggested.     

ATR-FTIR experiments with chlorosilanes

OH groups on the surface of semiconductors (SC) such as Si, Ge, TiO₂, SnO₂ react with Cl-Si groups to give stable SC-O-Si bonds. ATR-FTIR is applied to study the infrared spectra of adsorbed H₈Si₈O₁₂ on ZnSe and Cl₈Si₈O₁₂ which has reacted with the surface-OH group of Ge. A comparison is made with the spectra of the free molecules.     

甲基取代的氯硅烷甲醇醇解合成烷氧基硅烷

以有机氯硅烷与甲醇反应制备的烷氧基硅烷是有机硅工业的基本原料之一 ,也是有机硅工业中的重要中间体[1 ] 。本文以二甲基、三甲基氯硅烷和甲醇为原料 ,采用溶剂法的醇解方法来合成烷氧基硅烷 ,从醇解温度、溶剂种类及其滴加方式等影响因素 ,考察了甲醇醇解的难易程度和目的产物的得率 ,初步对其醇解规律进行了探讨。1　实验方法1 1　甲基一甲氧基硅烷的合成在 1 0 0ｍｌ三颈瓶中加块状金属钠 5 0克 ,缓慢滴加 35 0克甲醇 ,制得甲醇钠 -醇饱和溶液 ,备用。在三颈瓶中加入 1 0ｍｌ二甲苯作溶剂 ,氮气保护下 ,同时缓慢滴加甲醇钠 -醇饱和…     

Aminolysis of diphenyldichlorosilane and heterocyclic chlorosilanes

Reaction of diphenyldichlorosilane, dichlorosila fluorene, and dichlorosiloxarophenanthrene with amines in mono- or disubstituted organoaminosilanes gave mono- or disubstituted organoaminosilanes.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 754–756, June, 1976.     

Hexachloroethane: a highly efficient reagent for the synthesis of chlorosilanes from hydrosilanes

A new and efficient chlorination protocol is presented for the preparation of chlorosilanes from hydrosilanes. A variety of chlorinating agents in combination with palladium(II) chloride as the catalyst are examined. Among them, hexachloroethane is found to be the best choice, furnishing the desired product in good to quantitative yields under mild conditions. Various hydrosilanes are used as starting materials to explore the scope of this reaction.     

Controlled introduction of allylic group to chlorosilanes

Allylation of chlorosilanes has been achieved with allylsamarium bromide, especially in a controlled manner. Thus allylation of trisubstituted chlorosilanes (R₃SiCl) afforded a variety of aryl, aralkyl, and alkenyl substituted allylsilanes. Dichlorosilanes (R₂SiCl₂) can either afford monoallylated silanes or diallylated silanes depending on the amount of allylsamarium bromide used. Similarly, trichlorosilanes (RSiCl₃) can selectively afford mono-, di-, and tri-allylation products. Finally, perchlorosilane (SiCl₄) was allylated stepwise and the corresponding silanes containing one, two, three or four allylic groups, respectively, were obtained in satisfactory yields.     

Synthesis of organofunctionalized polysiloxane from polymeric tributylstannyl ester of silicic acid and chlorosilanes

Polymeric tributylstannyl ester of silicic acid (PTBS) was demonstrated to be an effective material for the preparation of functionalized polysiloxane derivatives (2). The reaction of PTBS and monochlorosilane (1), which possessed an organofunctional group such as the acetoxy or methylmethacrylate group, proceeded readily at room temperature under neutral conditions to give 2 with the elimination of the tributyltin group. The molecular weight of 2 estimated by GPC measurement was almost the same as that of starting PTBS. Such metal-exchange reaction was applicable for the incorporation of two kinds of silyl units into polysiloxane 2 by employing these monochlorosilanes 1 at the same time in the reaction. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2363–2369, 1999     

Protection of lithium metal surfaces using chlorosilanes

In this paper, we present a new approach for protecting metallic lithium surfaces based on a reaction between the thin native layer of lithium hydroxide present on the surface and various chlorosilane derivatives. The chemical composition of the resulting layer and the chemistry involved in layer formation were analyzed by polarization modulated infrared reflection absorption spectroscopy (PM-IRRAS), X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray analysis (EDX). Spectroscopy shows the disappearance of surface hydroxide groups and the appearance of silicon and chloride on the lithium surface. Differential scanning calorimetry (DSC) and electrochemical impedance spectroscopy (EIS) show that this surface treatment protects the lithium from certain gas-phase reactions and is ionically conductive.     

The synthesis of chlorosilanes from alkoxysilanes,silanols, and hydrosilanes with bulky substituents

We have found that commercially important trialkylchlorosilanes can readily be synthesized by the reaction of alkoxysilanes, silanols, and hydrosilanes with aqueous concentrated hydorochloric acid. Treatment of trialkylalkoxysilanes bearing the bulky alkyl substituents, such as the i-Pr, sec-Bu, tert-Bu, and cyclo-Hex group, with 35% aqueous hydrochloric acid afforded the corresponding trialkylchlorosilanes in excellent yields. Similar treatment of trialkylsilanols with 35% aqueous hydrochloric acid also gave trialkylchlorosilanes in almost quantitative yields. The reaction of methyltrichlorosilane and dimethyldichlorosilane with alkyl-Grignard reagents bearing a bulky alkyl group, followed by treatment of the resulting mixtures with aqueous concentrated hydrochloric acid, produced the respective dialkylmethyl- and alkyldimethylchlorosilanes in high yields. Treatment of trialkylhydrosilanes with concentrated hydrochloric acid in the presence of a palladium catalyst afforded trialkylchlorosilanes in high yields.     

s-Triazine and tri-s-triazine based organic-inorganic hybrid gels prepared from chlorosilanes by exchange reactions

Hybrid polymers [(DeltaO3)4Si3]n and [(DeltaO3)SiMe]n (where Delta = C6N7 or C3N3) have been prepared by a novel sol-gel process based on exchange reactions of MeSiCl3 or SiCl4 with C6N7(OSiMe3)3 and C3N3(OSiMe3)3.     

Synthesis and hydrolysis of fluoropyridinyl containing chlorosilanes

2-Fluoro-3-dimethylchlorosilylpyridine (A) and 3-fluoro-4-dimethylchlorosilylpyridine (B) were synthesized from the corresponding fluoro-lithio-pyridines and dimethyldichlorosilane at −76°C. The liquid products were unstable on standing. A and B were hydrolyzed in aqueous ammonia at room temperature to give disiloxanes which are stable crystalline solids. The new compounds were characterized by IR, ¹H NMR and MS.     

Palladium-catalyzed dimerization disilylation of 1,3-butadiene with chlorosilanes

[reaction: see text] 1,3-Butadiene reacted with chlorosilanes and Grignard reagents at 20 degrees C in the presence of a catalytic amount of Pd(acac)(2) to give disilylated dimers 2 regioselectively, which have two silyl groups (R(3)Si) at the 3- and 8-positions of a 1,6-octadiene skeleton. When phenyl- or allyl-substituted chlorosilanes were used, coupling product was obtained stereo- as well as regioselectively, giving rise to only (E)-olefins. It is proposed that Pd-ate complexes play important roles in both C-Si bond-forming processes.     

Heterofunctional condensation of chlorosilanes with tetra- and hexaphenylsiloxanediols

A number of new chloro- and hydrochlorosiloxanes with cyclic and linear structures were synthesized by the condensation of tetraphenyldisiloxane-1,3-diol and hexaphenyltrisiloxane-1,5-diol with silicon tetrachloride and trichlorosilane. The effects of the starting ratio of the reactants and dilution on the reaction rates and yields of cyclosiloxanes were studied.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 893–896, July, 1972.